Very Wide Band Absorption of Sunlight Spectra using Titanium Dioxide Particles with Distributed Band Gap

In this report we proposed an alternative approach to improve the absorption of solar radiation by titanium dioxide (TiO2) particles. We did not dope pure TiO2 with appropriate elements, but we just searched for low-grade (technical grade) TiO2 in the market. We assumed low grade TiO2s are those containing dopant atoms of different concentrations and of different elements. By inspecting the UV-Vis spectra of the samples we finally found TiO2 that absorbs nearly all visible spectra (from less than 200 nm to more than 800 nm). By assuming the powder consisted of distributed band gaps, we proposed a simple method for calculating the band gap distribution. We also used the TiO2 for making a prototype of solar cell and for a photocatalys to decompose organic pollutants in water, both are under sunlight illumination.